As a technique related to the present invention, there is, for example, a signal processing circuit described in Patent Literature 1.
In the signal processing circuit of Patent Literature 1, there is shown a signal processing circuit in which the same encryption processes are performed in parallel by a plurality of circuits that perform logically the same processes.
More specifically, the signal processing circuit of Patent Literature 1 includes a first circuit that performs an encryption related process; and a second circuit that performs an encryption related process which is logically the same as that performed by the first circuit.
Then, the second circuit is provided with a reversal circuit that reverses the polarity of a signal bit. An output from a first node among a plurality of nodes composing the first circuit is compared with an output from a second node among a plurality of nodes composing the second circuit that is provided at a location corresponding to the location of the first node of the first circuit. When the polarities of the two outputs are not reversed with respect to each other, the encryption related processes performed by the first circuit and the second circuit are stopped.